It is known in the art that the standard size of a compact disk (hereinafter, “CD”) on which information is recorded is that of a circle having a diameter of 12 cm or 8 cm. Recently, besides the CD of standard size, a rectangular CD which has a length of about 85 to 89 mm and a width of about 55 to 60 mm, and which includes a central hole and an annular information recording area provided outward of a clamping area has appeared. The CD of this type is referred to as “a business-card type CD” or “a card type CD” from its size.
The business-card type CD of no regular size is difficult to be installed on an existing disk player without any modification. This is due to the difficulty in positioning or centering business-card type CDs properly for recording and reproducing within the disk player. Therefore, a business-card type CD which has a positioning projection provided on a lower surface of the disk, fitted into an 8 cm CD mounting concave portion of a transport tray of a disk player, and used to perform the positioning or centering has been proposed (see WO99/0765 and the like).
Nevertheless, even the business-card type CD including such a positioning means cannot be installed in the existing disk player without a transport tray, particularly a slot-in or vertical disk player.
Japanese Patent Application Laid-Open No. 2000-11573 discloses a business-card type CD adapter capable of installing a business-card type CD in such a slot-in or vertical disk player.
Meanwhile, while the standard size of the circular CD is set to have a diameter of 12 cm or 8 cm, no standard size is set at present for the CD referred to as the business-card type CD. Therefore, as already stated, business-card type CDs of various sizes are commercially available.
The business-card type CD adapter disclosed in the Japanese Patent Application Laid-Open No. 2000-11573 can be used for the business-card type CD of a specific size, and cannot be used for the business-card type CD of a size different from the specific size. This business-card type CD is made of elastic material. For this reason, if the difference in length, width, and thickness between the business-card type CD of a specific size and that of different size is about 0.3 mm, the latter CD can be forcedly installed in the adapter. However, this CD is likely to be detached from the adapter within the disk player while it is subjected to a vertical or a rotational movement within the disk player.
The present invention has tackled the problems pointed out above. Therefore, it is an object of the present invention to provide a non-circular optical disk adapter capable of installing disks of different size and facilitating the disk installation operation.
Other objects of the present invention will be readily apparent from the embodiments to be described later.